"Concorde did not use turbine engines, and was more like a rocket in its operation, so it could fly without these problems - but at the cost of fuel efficency - and ticket prices!"
Uh, dude, I think you need to recheck your sources on that one. She had afterburning turbojets, like a fighter plane. I hope you are not assuming rocket just because there as a bright flame coming out the back of those engines....
As for higher, think of this: the total surface area of the fuselage of a bizjet is small compared to the total area of an airliner with respect to the stress that their fuselages can take. With the same material, a smaller plane will fly higher than a larger plane of a very specific design. That is my guess.
Cuz when you go higher up the air pressure drops like a brick, as it will drop about 10 times per 10 miles up. Therefore, at 20 miles it is 100 times less than sea level and so on.
Certain wing designs need lift and may not be able to stay in the sky it the air is too thin and it is just as well with certain engines. Thinner the air less thrust, less thrust means it will go slower until it stalls way up there, which is not good. The faster you go the less thin air seems, this is evident if you stick out hand out the window of a car at different speeds, it feels thicker when you are faster. For Concorde's wing design, it has to go above Mach just to keep from stalling way up there at FL600.
Here is a thought: NASA's pathfinder plane by Aerovironment is a solar electric airplane that flies at 20kts and at FL1000, it has a light wing loading and thick wing cross section. Rather contradicts would you would normally think, huh?
Uh, don't confuse the guy with suborbital altitudes, I think he'll assume space flight after that ignorant Concorde comment.
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